We have a samsung smart tv and we tried to use hulu on it and the cox box was on as well as the souround sound system. The only thing we hear is the cable box how do we fix it to where we hear hulu and not the cable box.
This has nothing to do with the cable box, when watching a smart tv, the cable box is not used at all.
Do you have the smart tv connected back to your surround sound system, if so how? Normally, you will connect them using either the Audio Return Channel (ARC) of the hdmi connection or a separate digital audio feed like fiber TOSLINK. Once the connection is in place, it's as simple as switching the surround sound system to the proper input. See your TV and audio system manuals for instructions (or if even supported) for using ARC.
My guess is the only audio you have going into the surround sound is the cable box, so that is the only thing you are going to hear from it. Since Hula is played by a app inside the TV, the sound from the TV will only be heard on the TV speakers unless you output the TV's audio to the surround sound system.
If you do have the audio output from the TV going into the surround but it isn't working, then +1 AllenP's thoughts and ideas.
